The New Yorker has published a previously unknown short story by Ernest Hemingway.

The author’s “Pursuit as Happiness” appeared in the latest issue of the magazine. The story was discovered by Hemingway’s grandson, Seán Hemingway, an art curator, at the at the John F. Kennedy Library and Museum in Boston, home to many of the author’s manuscripts.

Seán Hemingway told the New Yorker that he happened upon the story when he was preparing a new edition of his grandfather’s classic novel The Old Man and the Sea.

“The story exists in a single typewritten manuscript with emendations in Hemingway’s hand,” the younger Hemingway said. “I was surprised and excited by it and thought it would make a wonderful addition to the new edition.”

The story follows a fisherman on a quest to catch a gigantic marlin. Seán Hemingway said the story was almost certainly inspired by an actual fishing trip his grandfather took.

“Actually, I find it difficult to classify as fiction or nonfiction because much of the story is autobiographical, but I do prefer to think of it as fiction,” he said. “It is carefully crafted and reads like a short work of fiction.”

The story was untitled when it was discovered; it was given its name by Ernest Hemingway’s son Patrick.

“I think it is a very apt title for this unpublished story, because it is not just about catching and losing a large marlin—in the same way that The Old Man and the Sea is not just about catching and losing a large marlin to sharks,” Seán Hemingway said. “It is about the joy of fishing and the happiness that it brings.”

The Hemingway Library Edition of The Old Man and the Sea will be published by Scribner on July 21.

Michael Schaub is a Texas-based journalist and regular contributor to NPR.